Add support for demangling msvc's noexcept types to llvm-undname

[zahen]

Summary

msvc under C++17 mangles noexcept functions used as types (function parameters, template types) with "_E" instead of "Z" indicating the function is noexcept.

[rnk]

lgtm

[zahen]

Same as the corresponding mangling patch, I'd appreciate someone else landing this since I don't have check-in permission.

[rnk]

Oops, too many Zacharies. I mistook you for him (only in this patch, not the other one). He has more ownership over this code, so I will let him approve it.

[zturner]

lgtm. I'm technically on vacation so rnk@ might be able to commit it sooner than I can, but if he doesn't, then I'll commit it when I find some spare cycles. Thanks for fixing this!

[zahen]

In D55769#1333778, @zturner wrote:

lgtm. I'm technically on vacation so rnk@ might be able to commit it sooner than I can, but if he doesn't, then I'll commit it when I find some spare cycles. Thanks for fixing this!

Hi @zturner, can you please commit this when you have a chance?

[kristina]

In D55769#1350029, @zahen wrote:

In D55769#1333778, @zturner wrote:

lgtm. I'm technically on vacation so rnk@ might be able to commit it sooner than I can, but if he doesn't, then I'll commit it when I find some spare cycles. Thanks for fixing this!

Hi @zturner, can you please commit this when you have a chance?

I don't mind doing it if there are no objections, as Zachary has signed off on it (may have to wait a bit, I'll run the tests with this applied first).

include/llvm/Demangle/MicrosoftDemangle.h

   FuncClass demangleFunctionClass(StringView &MangledName);
   CallingConv demangleCallingConvention(StringView &MangledName);
   StorageClass demangleVariableStorageClass(StringView &MangledName);
-  void demangleThrowSpecification(StringView &MangledName);
+  bool demangleThrowSpecification(StringView &MangledName);
   wchar_t demangleWcharLiteral(StringView &MangledName);
   uint8_t demangleCharLiteral(StringView &MangledName);
 

include/llvm/Demangle/MicrosoftDemangleNodes.h

 
   // Function parameters
   NodeArrayNode *Params = nullptr;
+
+  // True if the function type is noexcept
+  bool IsNoexcept = false;
 };
 
 struct IdentifierNode : public Node {

lib/Demangle/MicrosoftDemangle.cpp

   return Ty;
 }
 
-void Demangler::demangleThrowSpecification(StringView &MangledName) {
+bool Demangler::demangleThrowSpecification(StringView &MangledName) {
+  if (MangledName.consumeFront("_E"))
+    return true;
   if (MangledName.consumeFront('Z'))
-    return;
+    return false;
 
   Error = true;
+  return false;
 }
 
 FunctionSignatureNode *Demangler::demangleFunctionType(StringView &MangledName,

 
   FTy->Params = demangleFunctionParameterList(MangledName);
 
-  demangleThrowSpecification(MangledName);
+  FTy->IsNoexcept = demangleThrowSpecification(MangledName);
 
   return FTy;
 }

lib/Demangle/MicrosoftDemangleNodes.cpp

   if (Quals & Q_Unaligned)
     OS << " __unaligned";
 
+  if (IsNoexcept)
+    OS << " noexcept";
+
   if (RefQualifier == FunctionRefQualifier::Reference)
     OS << " &";
   else if (RefQualifier == FunctionRefQualifier::RValueReference)

test/Demangle/ms-cxx17-noexcept.test

+; RUN: llvm-undname < %s | FileCheck %s
+
+; CHECK-NOT: Invalid mangled name
+
+?nochange@@YAXXZ
+; CHECK: void __cdecl nochange(void)
+
+?a@@YAXP6AHXZ@Z
+; CHECK: void __cdecl a(int (__cdecl *)(void))
+?a@@YAXP6AHX_E@Z
+; CHECK: void __cdecl a(int (__cdecl *)(void) noexcept)
+
+?b@@YAXP6AHXZ@Z
+; CHECK: void __cdecl b(int (__cdecl *)(void))
+
+?c@@YAXP6AHXZ@Z
+; CHECK: void __cdecl c(int (__cdecl *)(void))
+?c@@YAXP6AHX_E@Z
+; CHECK: void __cdecl c(int (__cdecl *)(void) noexcept)
+
+?ee@?$e@$$A6AXXZ@@EEAAXXZ
+; CHECK: private: virtual void __cdecl e<void __cdecl(void)>::ee(void)
+
+?ee@?$e@$$A6AXX_E@@EEAAXXZ
+; CHECK: private: virtual void __cdecl e<void __cdecl(void) noexcept>::ee(void)